diff --git a/src/main/java/edu/harvard/iq/dataverse/util/json/JsonPrinter.java b/src/main/java/edu/harvard/iq/dataverse/util/json/JsonPrinter.java
index d9f19f1e94e..f6a64e5fe6a 100644
--- a/src/main/java/edu/harvard/iq/dataverse/util/json/JsonPrinter.java
+++ b/src/main/java/edu/harvard/iq/dataverse/util/json/JsonPrinter.java
@@ -657,7 +657,7 @@ public static JsonObjectBuilder json(FileMetadata fmd){
     }
 
     public static JsonObjectBuilder json(FileMetadata fmd, boolean returnOwners, boolean printDatasetVersion) {
-        JsonObjectBuilder builder = jsonObjectBuilder();
+        NullSafeJsonBuilder builder = jsonObjectBuilder();
 
                 // deprecated: .add("category", fmd.getCategory())
                 // TODO: uh, figure out what to do here... it's deprecated